Dave, UR: Small victories are still victories

 Big news! Two out of the three necessary hydrophones for my research are secure! I am now exceptionally glad that I have developed strong and confident social skills over the years. Thanks to Dr. Hong Liu over at Embry-Riddle Aeronautical University, we have two Sparton PHOD-1 hydrophones on loan, for the low-low price of sharing my research data (which I'm cool with anyway).

On a campus visit with DSC's STEM Community Scholars Program last semester, I met Dr. Liu as he displayed his Eco-Dolphin project. You can bet your last penny that we talked all about dolphins, and he offered his assistance in my research. After doing some window shopping of research-grade hydrophones, we found them to be prohibitively expensive, and decided to call in a favor. If you would like to follow Dr. Liu's team as they work on their Eco Dolphin, I would encourage you to swing by the website at: http://www.eco-dolphin.org/ 

The PHOD-1's are close enough to the Cetacean Research CR1's that we were looking at, and we still have to find one more hydrophone. For the sake of this experiment, keeping the identical PHOD-1's on the bottom of the array will be sufficient. Whatever our other hydrophone ends up being, will remain at the top (zero degree) position, and will be observed for performance differences during the first baseline collection. That baseline collection will be conducted with flat collector plates, so that changes in performance of collector dishes can be observed as the dishes tighten in angle.

Hydrophones are clamped in by the component that the collector dishes mount to.

The objectives of this phase of development are direct, and future developments will be shared on the Team's blog after I transfer when the semester ends. These goals are:

• Verify structural materials in a non-laboratory environment 
• Determine optimal shape and angle of collector dishes for acute sound collection
• Determine optimal array radius for acute collection while minimizing interference

A well-constructed hydrophone array will open research opportunities!

On to structural materials. We wanted to use something for our initial structural prototypes that would be cheap to 3d-print, but could be strong enough to handle the added density of water. Remember how I told you that water is more than 800 times more dense than air? Structural materials decisions become more complicated when you add water. So, for cheap and durable, we opted for plastic.

Now hold onto your trees, hippies! Not all plastics are evil! We chose to prototype with PLA Plastic because it is cheap, strong, found in most 3d-printing labs in bulk, and also...biodegradable. Polylactic Acid (PLA) is a thermoplastic aliphatic polyester derived from renewable resources, such as corn starch, tapioca roots, and sugarcane.  For the chemists in the crowd that would like to know more about how good science paved the road for biodegradable structural materials, the Wikipedia entry on Polylactic Acid is very comprehensive.

We still have more work to do before the first dive, so as we approach dive time, I will explain the in-pool specifics of what we want to achieve in the water, and how we plan to do it.

Get a grip! Grips on the rear were angled to be more ergonomic for the diver holding the array.